Which O2 Sensor to replace?

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dimax

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I just got a 2014 Ram 1500 5.7 and first thing I noticed is that it's using a lot of fuel.

I'm getting barely 10mpg while my friend with the same truck is getting 14-16.

I found a 1622 code related to the o2 sensor.
So I'm guessing that maybe the sensor is messing with the car and making it burn more fuel?

I checked and there are various o2 sensors. By the cat. converter.
by the drivers and passenger side

I took a pic of the drivers side but It looks like there are 2 near the exhaust manifold and I'm not sure which one to mess with?

Thanks in advance


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White six four

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The downstream sensors shouldn't have anything to do with the air fuel ratio. They are there to monitor the cats and make sure they are working properly. The upstream o2 sensors are the ones that can affect the air fuel ratio and cause poor gas mileage if they're bad/worn out.

Replace them with oem if you do.
 

62Blazer

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That codes is saying you have a high reference voltage coming from the upstream O2 sensors on each bank (so the sensors on each exhaust downpipe coming out of the engine, and NOT the ones after the cat). Look at the short term and long term fuel trims on your scanner, as indicated by STFT and LTFT for both banks. In your one picture you can see the STFT for bank 1. It states 25% which means based on the reading from the bank 1 O2 sensor it thinks the engine is running lean and demanding to increase fuel (richen up). If this reading is wrong, meaning the engine is running just fine but a bad sensor reading and demanding a lot more fuel, it would cause your issue. I would see what the STFT for bank 2 states and both LTFT's. In most conditions I would suspect the fuel trims to be under 10%, and probably closer to 5%.

If the STFT for bank 1 states 25% and for bank 2 it is only maybe 5%, than the problem is likely isolated to bank 1 (driver's side). If both banks have a high reading there is something going on with both sides/banks. While the sensor could be bad, from my experience at least half of the times the actual sensor is okay and the problem is in the wiring or connectors. I would look for any damaged or rubbed through wiring that was shorting out.

Just as an FYI, the "CL" shown the scanner screen for fuel systems 1 and 2 stand for closed loop. When the engine is cold it will say "OL" for open loop. Then you first start the engine and it's cold, it is running on a pre-mapped program regarding how much fuel it provides and not relying on the O2 sensors. This is because the O2 sensors have to heat up and the exhaust has to heat up before they give an accurate signal. The engine will go into closed loop once warmed up and will start adjusting the fuel based on input from the O2 sensors.
 
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dimax

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@62Blazer OMG thanks so much for your help!!!
Just came back from a trip so I didn't see your message until now.

I just checked the bank 1 sensor and it looks like it was replaced recently. Shiny and New. The Bank 2 is rotten but that one gives okay readings.

The o2 sensor s connection seems to be okay. But maybe they put in a cheap one and its causing bas readings (?

Before messing with the left sensor, is there anything I should check first like valves or other sensors?
The engine light is annoying me and I'm trying to fix it before I sell the car

Thanks
 
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